1. Field of the Invention
The present invention generally relates to automobile wheels equipped with decorative overlays. More specifically, this invention relates to a wheel and overlay assembly in which the overlay extends radially outward to the flange of the wheel so as to cover the entire outboard surface of the wheel, and the wheel flange and overlay are complementarily configured to enable a standard balance weight to be secured to the wheel flange.
2. Description of the Prior Art
Decorative overlays are widely used to enhance the aesthetic appearance of automotive wheels. Overlays are not only employed to improve the appearance of unadorned standard steel wheels, but are also used with cast aluminum wheels, which are known to be difficult to plate with chromium. A wheel and overlay assembly of a type known in the prior art is illustrated in FIG. 1. The assembly is generally composed of an overlay 16 secured to the wheel's outboard surface, defined here by a wheel disk 14 to which a rim portion 12 is welded. The wheel further includes a rim flange 10 that projects in a radially outward direction from the wheel, terminating in a flange lip 20 that extends axially from the rim flange 10 in an outboard direction, such that the flange lip 20 circumscribes the outboard surface of the wheel. As the term is used herein, the flange lip 20 does not form a part of the wheel's outboard surface, which denotes the generally radially extending surface of the wheel on the laterally outward side of a vehicle to which the wheel is mounted. As is conventional, a balance weight 24 is shown as being mounted to the rim flange 10 for the purpose of balancing the wheel assembly.
The overlay 16 shown in FIG. 1 is particularly of the type taught by Chase in U.S. patent application Ser. No. 07/904,180, filed Jun. 25, 1992, entitled "Chromium-Plated Composite Wheel" now abandoned and U.S. patent application Ser. No. 08/312,144, filed Sep. 26, 1994, entitled "Heat-Resistant Overlay for an Automotive Steel Wheel", both of which are assigned to Lacks Industries, Inc., the assignee hereof. As such, the overlay 16 is a metal plated or painted plastic panel that is formed independently and separately from the wheel. The overlay is permanently adhered directly to the outboard surface of the wheel, preferably with a high temperature adhesive such as a silicone or polyurethane. Notably, the disclosed metal plating process enables the overlay 16 to closely conform to the outboard surface and cover high temperature regions of the wheel that conventional overlays are incapable of withstanding.
While the overlay 16 of FIG. 1 has distinct advantages over previous overlays and assembly methods, a shortcoming is that the radially outward edge 22 of the overlay 16 must extend short of the flange lip 20 of the rim flange 10 so as to enable the wheel balance weight 24 to be secured to the flange lip 20. As those skilled in the art are aware, balance weights are manufactured in standardized configurations in order to permit interchangeability with various wheel designs. Four of the more common standardized types are letter coded as P, C and T types, adapted to be mounted to steel wheels, and the MC type, adapted to be mounted to cast aluminum wheels. In order for the balance weight 24 to be reliably secured to the flange lip 20 with an interference fit, certain dimensions of the balance weight 24 and rim flange 10 must be within appropriate tolerances. For such purposes, the Society of Automotive Engineers (SAE) has adapted standards for MC type wheels as well as for the most common type steel wheels. As identified in FIG. 1, such dimensions include the flange lip thickness "T", measured in a radial direction relative to the wheel; the flange width "W", defined as the distance in the axial direction of the wheel from the outboard tip of the flange lip 20 to the inboard surface of the rim flange 10; and the flange offset "O", defined as the distance in the axial direction of the wheel from the outboard tip of the flange lip 20 to the outboard surface of the rim flange 10. The key dimensions for the balance weight 24 are the thickness of the weight measured in the axial direction when installed, and the gap width between the base portion of the weight and the inner diameter of the weight's clip 30. The flange offset "O" and balance weight thickness are critical for accommodating the balance weight 24 on the rim flange 10, while the flange thickness "T" and the clip's gap width are critical for achieving an adequate interference fit in order to retain the balance weight 24 on the rim flange 10. As will be apparent, the weight's interference fit is dependent on the ability of the flange offset "O" to fully accommodate the balance weight 24 on the rim flange 10.
In the prior art, standard flange and balance weight dimensions have prevented overlays such as the overlay 16 of FIG. 1 from extending up to the flange lip 20, in that doing so would prevent a standard balance weight 24 from being positioned sufficiently onto the flange lip 20 in order to gain the full benefit of the interference fit between the balance weight clip 30 and the flange lip 20. Because of the limited coverage of the wheel's outboard surface by the overlay 16, the resulting styling effect of the wheel assembly of FIG. 1 is somewhat less than optimum, particularly if the overlay 16 is chromium plated and therefore conspicuously contrasts the dull surface of the wheel. Another consequence is that, because a portion of the outboard surface remains visible, the two-piece construction of the wheel assembly is betrayed, diminishing the wheel assembly's perceived value. Another possible effect is that the wheel assembly may appear smaller to a casual observer, contrary to the styling objectives of many designers.
U.S. Pat. No. 2,926,953 to Lyon overcomes some of the above-noted shortcomings by disclosing a wheel cover that extends out to the wheel flange so as to conceal essentially the entire outboard surface of the wheel. However, the wheel cover lacks the significant aesthetic and structural advantages of an overlay that is directly and permanently bonded to the wheel's outboard surface, such as the type taught by Chase. Furthermore, the wheel cover necessitates the use of balance weights that are not of a standardized type. As such, there is considerable reluctance in the industry to adopt a solution such as Lyon's, particularly in view of the difficulty with which such an approach would be implemented by automobile service facilities.
Accordingly, what is needed is a wheel and overlay assembly that is specifically configured to enable the overlay to completely cover the outboard surface of the wheel so as to maximize the overlay's intended decorative effect, while also enabling standard balance weights to be readily and reliably mounted to the wheel's rim flange so as to permit proper balancing of the wheel and overlay assembly.